1. Field of the Invention
The present invention relates in general to the field of liquid storage systems. In particular, the present invention provides a greatly improved method and apparatus for storing waste oil products above the ground.
2. Description of Related Art
In recent years significant levels of concern have been raised over the use of below-ground liquid storage vessels such as tanks. Such vessels have in the past been used to store a wide variety of materials including gasoline, waste oil, and a myriad of other chemicals. Problems arise when the vessel begins to leak due to corrosion and the like and allows a stream of material to leak into the surrounding soil without detection over a long period of time. After entering the soil, these materials percolate downward into, for example, ground water supplies. This represents a clear environmental danger. Equipping underground vessels to be environmentally safe is extremely expensive. Monitoring and repair of underground vessels is also expensive and complex.
As a consequence, above-ground storage vessels are becoming more frequently used. By using an above-ground storage tank it is possible to more closely monitor leaks, primarily because the tank is fully visible. Further, the tank is less likely to leak in the first instance because it may be maintained with paint and the like.
In the prior art, a single-walled above-ground tank is placed in a "containment" area. Typically, the containment area is a mound of soil, a concrete floor and walls, or other similar type of area which forms a wall (or "berm"). There are, however, a number of problems associated with the use of these above-ground storage systems. Initially the "system" is almost by definition not portable because large volumes of soil must be moved to form the berm, or concrete must be poured to form the berm. Further, in the event of a leak, the material within the tank is widely exposed, creating the likelihood of release of air contaminants and the likelihood of injury to passers-by. They further are not totally impervious to leakage (unless frequently treated with a sealant) due to their porous nature. Another problem with prior systems is that the open and uncovered berms are subject to being filled with rain water and other trash debris. Mixed with product spillage into the secondary containment, this water and debris is considered "contaminated" and must be disposed of accordingly.
It is clear that an improved method and apparatus for the storage of waste oil and other contaminants is needed.